[1] Kansai Med Univ, Dept Obstet & Gynecol, Hirakata Hosp, Osaka 5731191, Japan
[2] Kanagawa Childrens Med Ctr, Dept Pediat, Yokohama, Kanagawa, Japan
[3] Univ Toronto, Hosp Sick Children, Dept Diagnost Imaging, Toronto, ON M5G 1X8, Canada
[4] Univ Toronto, Hosp Sick Children, Dept Pediat, Div Cardiol, Toronto, ON M5G 1X8, Canada